Here is a simple #java digital clock idea that can be used as the bases for something allot nicer or even eventually a eye candy widge/icon/desklet is you are artistically inclined.
This is the simple outcome and as you can see very simple but a nice starting point.
Here you have a code snip of the ClockLabel
ClockLabel clock = new ClockLabel();
clock.setFont(new Font("Comic Sans MS", Font.BOLD, 20));
The full code is here SimpleJavaClock you can simply copy and paste and compile and run.
This is how you compile via command line:
$ javac SimpleJavaClock.java
$ java -cp . SimpleJavaClock
If you are going to compile and run via command line the easiest thing to do is remove the first line of the code (package name)